Appropriate Workup for Slow Cognition

Initial Assessment

The American College of Physicians recommends obtaining detailed history focusing on cognitive abilities, including onset and nature of cognitive loss, and collecting corroborative history from a reliable informant using structured tools like AD8 or Alzheimer's Questionnaire (AQ) 1
The appropriate workup should assess for specific triggers that may contribute to cognitive symptoms, such as preceding viral infections or fever, and evaluate medication use, as certain medications can contribute to cognitive symptoms 2
The initial assessment should also include evaluation of medication use, as certain medications (especially anticholinergics or sedative hypnotics) can contribute to cognitive symptoms 1, 2

The Journal of Internal Medicine suggests using AQ or AD8 if an informant is available, or Memory Impairment Screen (MIS) or Montreal Cognitive Assessment (MoCA) if no informant is available, to assess cognitive domains 1
The assessment should include evaluation of specific cognitive domains: memory, executive function, visuospatial abilities, language functions, and personality/behavior changes 2, 3
The Clock Drawing Test can be a useful supplementary screening tool for cognitive assessment 2

Complete blood count with differential should be ordered to rule out anemia, and comprehensive metabolic panel including electrolytes, calcium, magnesium, and liver function tests should be checked 1, 2
Thyroid function tests, vitamin B12, homocysteine, and folate levels should be measured, and inflammatory markers (erythrocyte sedimentation rate and C-reactive protein) should be included 1

Structural brain imaging with MRI (or head CT if MRI is contraindicated) should be obtained, particularly when there is onset of cognitive symptoms within the past 2 years, unexpected decline in cognition/function, or significant vascular risk factors 1, 2

Referral to a neurologist, geriatrician, geriatric psychiatrist, neuropsychologist, or dementia subspecialist may be beneficial for detailed assessment of cognitive domains 1
Advanced biomarkers such as lumbar puncture to assess for Aβ, tau, p-tau, Amyloid PET or Tau PET imaging, and blood-based biomarkers (BBMs) may be considered for suspected Alzheimer's disease 1, 4

Screening for depression and anxiety, which can manifest as or exacerbate cognitive symptoms, is recommended 2
Assessment for risk factors for cognitive decline, including cerebrovascular risk factors and diabetes mellitus, should be conducted 1

Failing to obtain corroborative history from an informant, which is essential for accurate assessment, should be avoided 2
Overlooking medical conditions that can influence biomarker interpretation, such as obesity or chronic kidney disease, should be avoided 2

Follow-up visits every 6-12 months to track disease progression, using a multi-dimensional approach to monitor cognition, functional autonomy, behavioral symptoms, and caregiver burden, are recommended 5, 3

A focused laboratory panel—including comprehensive metabolic panel, thyroid function tests, vitamin B12/folate, complete blood count with differential, and urinalysis—is recommended to uncover reversible metabolic, endocrine, nutritional, hematologic, and infectious contributors to cognitive decline in older adults. 6
In older adults, a complete blood count with differential assists in detecting anemia and infection, conditions that disproportionately affect individuals with cognitive impairment. 6
Urinalysis should be performed to identify urinary‑tract infection, a frequent acute precipitant of cognitive symptoms in the elderly. 6

Fasting glucose and hemoglobin A1c testing are advised to screen for diabetes, which is linked to decreased cognitive function in older adults. 7

A systematic review of all medications is essential to identify anticholinergic agents or sedative‑hypnotics that commonly impair cognition in older patients. 6

Brain MRI (preferred over CT) is indicated when cognitive symptoms have begun within the past 2 years, there is unexpected decline in cognition or function, recent head trauma, unexplained neurological signs, or the presence of significant vascular risk factors. 8